Skeleton frameworks in the form of trusses, space frames and lattice-works are well known in the art for supporting various objects or for forming load bearing walls for building structures. Unfortunately, many of these prior art structures are very expensive to mass produce since the joints coupling the elongated beams or struts forming the structure have traditionally been very complicated, require extensive machining and require numerous fasteners such as nuts and bolts. In addition, many of these prior art structures are very difficult to assemble and are heavy.
Moreover, many of the prior art structures utilize joints which do not adequately rigidly couple the elongated members forming the structure, which can result in failure after initial erection. Many of these prior art structures also do not utilize tubular beams, but instead utilize solid rods which are very expensive to make, are very heavy and do not have great resistance to bending.
In those cases where tubular beams are used, for example, as diagonal members interconnecting two planar arrays of beams and joints, the beams traditionally require large outer diameters to withstand the bending moments to which they are subjected. This adds expense and weight to the entire structure.
Such prior art structures are disclosed in the following U.S. Pat. Nos. 2,964,147, issued to Fentiman on Dec. 13, 1960; 2,976,968, issued to Fentiman on Mar. 28, 1961; 3,270,478 issued to Attwood on Sept. 6, 1966; 3,309,121, issued to Fentiman on Mar. 14, 1967; 3,323,820, issued to Braccini on June 6, 1967; 3,443,348, issued to Papayoti on May 13, 1969; 3,485,005, issued to Kutchai on Dec. 23, 1969; 3,914,063, issued to Papayoti on Oct. 21, 1975; and 3,918,233, issued to Simpson on Nov. 11, 1975. In addition, such prior art structures are disclosed in French Pat. No. 682,854, issued to Doornbos et al. on June 3, 1930; Italian Pat. No. 581,277, issued to Industria Officine Magliana on Aug. 25, 1958; and German Offenlegungsschrift No. 2,444,612, issued to Arab on Apr. 1, 1976.